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Best charge settings for Pylontech


Vard0

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Hello all.

I've recently upgraded to Pylontech batteries and I'm struggling to find the best charge settings on the inverter for them.

A couple of days ago I was getting error 77 (Parameter error) which seemed to go away after I changed the Float charge setting (although I'm not 100% sure this was the issue).  And last night (after 7:00 pm so no solar input - only mains) I got an error code 3 (Battery voltage is too high) followed shortly by error code 8 (Inverter bus voltage is too high).  I restarted the inverter and the batteries but the error code 8 came up again so I ended up disconnecting the inverter from the mains and running off batteries for the night.  

These are the settings as they currently are on the inverter:-

01 - SOL - Solar energy provides power to the loads as first priority.
Battery Type is Li - Lithium
Bulk Charging Voltage is 53.2V
Float Charging Voltage is 53.0V (I did have this set to 53.2V)
Low DC cutoff is 46.7V 
Battery stop discharging voltage when grid is available - 46V
Battery stop charging voltage when grid is available - 53.4V
 
It also seems that the inverter will stop charging as soon as the battery reaches the "stop charging voltage" and will not resume charging regardless of whether there is load or not.  I have to restart the inverter to get it charging again as you can see in the graph below.  So I'm really not sure what the best setting to be using here is.
 
image.png.4fd06689027243febcb0e837943a31f3.png
 
I would really appreciate some advice from the more experienced among us.  BTW the inverter is a voltronics clone and the plan is to upgrade as soon as I can, but in the meantime I'm stuck with this one unfortunately.
 
Cheers
 
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2 hours ago, Vard0 said:
Low DC cutoff is 46.7V 
Battery stop discharging voltage when grid is available - 46V
Battery stop charging voltage when grid is available - 53.4V

Yikes! 46 V is like 1% SOC, you should never be there. On a real Axpert, I don't think you can even set the low DC cutoff higher than the back to grid voltage.

I suggest trying around 47.8 (or 48 if that's not possible) for the stop discharging voltage. I'm assuming that this is the equivalent of the Axpert setting 12, back to utility voltage setting.

Something like 53 V for stop charging voltage; I'm assuming that this is the equivalent of the Axpert back to battery voltage setting (setting 13).

Try setting your low DC cutoff a fair bit lower than the battery stop discharging voltage. In Axperts, this should be at least 2.0 V, but your clone seems to at least understand Li batteries, so the gap could be much less, perhaps half a volt less than the battery stop discharging voltage.

The 53.2 V setting is 3.55 VPC, which is quite high. If your inverter overshoots as much as Axperts do, then this could cause problems. It could come down to as low as 51.8 V. The battery stop charging voltage should be less than this, by at least several tenths of a volt, it seems to me.

Good luck.

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  • 8 months later...

Coulomb, I have a question. I have two inverters in pal mode with 3 pylontrch U3000. Setting 2 the charging Amps was set as 50A per inverter by the installer. With the understanding that the inverters in pal mode will charge the batteries in combined mode of 50A(25A per inverter) but I noticed is not the case. It charged the batteries at between 80A and 100A. It is as if it combined the two 50A together to 100A. I have change that setting to 30A each. Now it is average just below 60A.

Is this ok. I can only set it at next setting to 20A each as it increments in 10.

It is Axpert Mercer 5k inverters

You can mail me if possible, [email protected].

Thanks

Jacques

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@vwykj, if you want to ensure that a member gets a notification that you asked for their help, use @Coulomb instead of Coulomb.

This particular question does not need his specialised expertise. Setting 2 on paralleled Axperts is independent and cumulative: 3 US3000s have recommended total charge current of 37x3 = 111A.  You can set one inverter at 60A and the other at 50A to get 110A.

 

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8 hours ago, vwykj said:

SBU or SOL?

SBU to minimise grid usage.

SOL to keep the battery as full as possible (good if you expect load shedding and battery capacity isn't large enough to comfortably ride out load sheds).

UTI if you are running a generator.

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  • 1 year later...

@Coulomb I have been upgrading the firmware on the first of my Pylontech batteries using the leaflet from Pylontech and the correct leads. V2.3 and v2.4 to V3.4. I have however hit a dialogue box which does not appear on the sheet. Can you advise what value should be put in this currently defaulted to 0. Thanksimage.thumb.png.68f30010bc751f25ec5b8ec229c01b5c.png

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I know nothing about updating the firmware of Pylontechs. My guess is that it wants the present capacity of the battery. For a US2000, that is presumably 50.0 Ah nominally, but I think it wants to know the present value with ageing, which might be about 49.5Ah, depending on many factors. I think you were supposed to extract that data from the BMS before updating the firmware. But I'm guessing.

If you know the SOH of the battery, say it was 98.7%, then you could enter 0.987 * 50.0 = 49.35 here. Again, guessing.

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  • 2 years later...

Hi @Coulomb

Regarding your advice below about the 48v, I am a bit confused now, also trying to interpret the Pylontech manual and how to set the charging settings correctly on my inverter.

The us3000c manual (attached) only states these values:

  • Discharge Voltage (V) 44.5 ~ 53.5
  • Charge Voltage (V) 52.5 ~ 53.5

Yet on the inverter, one has to set all these (with what I thought would be correct, in brackets):

  • Shutdown battery voltage (44.5V)
  • To grid battery voltage (45V-50V depending on reserve required)
  • Back to battery voltage (53.5V)
  • Battery float charge voltage (52.5V)
  • Battery absorption charge voltage (53.5V)

So if this is incorrect, how should one then interpret the manual's values to set the inverter correctly?

On 2020/01/24 at 3:20 PM, Coulomb said:

Yikes! 46 V is like 1% SOC, you should never be there. On a real Axpert, I don't think you can even set the low DC cutoff higher than the back to grid voltage.

I suggest trying around 47.8 (or 48 if that's not possible) for the stop discharging voltage. I'm assuming that this is the equivalent of the Axpert setting 12, back to utility voltage setting.

Something like 53 V for stop charging voltage; I'm assuming that this is the equivalent of the Axpert back to battery voltage setting (setting 13).

Try setting your low DC cutoff a fair bit lower than the battery stop discharging voltage. In Axperts, this should be at least 2.0 V, but your clone seems to at least understand Li batteries, so the gap could be much less, perhaps half a volt less than the battery stop discharging voltage.

The 53.2 V setting is 3.55 VPC, which is quite high. If your inverter overshoots as much as Axperts do, then this could cause problems. It could come down to as low as 51.8 V. The battery stop charging voltage should be less than this, by at least several tenths of a volt, it seems to me.

Good luck.

 

US3000C-MANUAL.pdf

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4 hours ago, PaulNaude01 said:

Hi @Coulomb

Regarding your advice below about the 48v, I am a bit confused now, also trying to interpret the Pylontech manual and how to set the charging settings correctly on my inverter.

The us3000c manual (attached) only states these values:

  • Discharge Voltage (V) 44.5 ~ 53.5
  • Charge Voltage (V) 52.5 ~ 53.5

Yet on the inverter, one has to set all these (with what I thought would be correct, in brackets):

  • Shutdown battery voltage (44.5V)
  • To grid battery voltage (45V-50V depending on reserve required)
  • Back to battery voltage (53.5V)
  • Battery float charge voltage (52.5V)
  • Battery absorption charge voltage (53.5V)

So if this is incorrect, how should one then interpret the manual's values to set the inverter correctly?

 

US3000C-MANUAL.pdf 1.57 MB · 0 downloads

We have seen some Axpert over shooting the maximum voltage set and the manufacturer denied a claim under warranty. 

Rather leave some 0.3V margin. 53.2V could be a good call. 

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I run a pack of 3 x u3000 Pylontechs  for 4years 6 months. The charging is set at 52.5v..The cells is still well balenced and the SOH is at 94%. Even at 52.5v the Axpert still overshoot tot 53.4 v. There is no benefit to charge at a higher voltage just the danger of exceeding The Pylontechs max charging  voltage.

.

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